Here's where I have to stand firm I'm not trying to start a flame war, but saying left or right orientation is irrelevant, is incorrect. Ryan says either work because an editor can fix your mistake, and let's be clear it is a mistake. Knowing which page is your turn page is what separates the professionals from the dabblers. All comic book artists have heard this -- know the rule before you break the rule!
A professional respects the medium, those asking the question are showing an interest in how the medium works. Dismissing the question of right left orientation as a non-question does not help writers get better at this medium, that is the reason why I answered with an explanation based on science as well as the medium. If you don't understand the medium you can understand the science. We can only get better by solving all the problems before the editorial stage. Our job as collaborators is to make the other artists' (writers, pencilers, inkers, letterers, colorists) jobs easier. If a penciler has to fix the pages because the writer didn't know which was his turn page -- a DC Senior Editor corrected me about not fixing the writer's errors in a trial script. (Ryan: I'm on their radar just haven't been given a chance yet) -- then that is considered the pencilers' fault. Making sure that writer's are aware of this is my responsibility, helping each other is why we are on this board.